String mycolor;
String msg="What is your color?(red/green/blue)";
int redPin=9;
int greenPin=10;
int bluePin=11;
int delayt=1000;

void setup() {
  // put your setup code here, to run once:
Serial.begin(9600);
pinMode(redPin, OUTPUT);
pinMode(greenPin, OUTPUT);
pinMode(bluePin, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
Serial.print(msg);
while(Serial.available()==0){

}
mycolor=Serial.readString();
if(mycolor=="red"){
  digitalWrite(redPin, HIGH);
  delay(delayt);
  digitalWrite(redPin,LOW);
  delay(delayt);
}
if(mycolor=="green"){
  digitalWrite(greenPin, HIGH);
  delay(delayt);
  digitalWrite(greenPin,LOW);
  delay(delayt);
}
if(mycolor=="blue"){
  digitalWrite(bluePin, HIGH);
  delay(delayt);
  digitalWrite(bluePin,LOW);
  delay(delayt);
}
}